Abstract: Objective: The mutagenic of cassava leaves was researched for its safe to use. Method: The relevant toxicology tests, including broad bean root tip micronucleus test /the micronucleus test of bone marrow cells in mice and sperm abnormality test in mice, were used to study the cassava leaves' s poisonous effect.Result: It was found that the broad bean root tip micronucleus rate would increase when the concentration of cassava leaves was above 15.80mg /mL, the micronucleus index was 1.77, and there was a significant difference between the group of experiment and the negative control ( p < 0.01) . It was discovered that the male and female mice bone marrow micronucleus rate was increased significantly when the concentration of cassava leaves was above 15.80mg /mL, compared with the negative control ( p < 0.05, p < 0.01) . When the concentration of cassava leaves was above7.90mg /mL, it was found that the male mice sperm malformation rate would increase, compared with negative control ( p < 0.01) .Conclusion: Deciding from this, a certain concentration of cassava leaves may have some harmful effect on the broad bean root tip cells /somatic cells and reproductive cells in mice.